1. Field of the Invention
The present invention relates to a transfer switch, especially to a transfer switch that has improved safety for use.
2. Description of the Prior Art(s)
A factory is electrically connected to a mains power source and an auxiliary power source. By switching a transfer switch, the mains power source and the auxiliary power source selectively provide electrical power to the factory.
A conventional transfer switch comprises a mounting seat, a main no-fuse circuit breaker, an auxiliary no-fuse breaker, a motor cover, and a switching control assembly. The main no-fuse circuit breaker, the auxiliary no-fuse breaker, and the motor cover are mounted on the mounting seat. The switching control assembly is mounted on the motor cover and has a gear set. The gear set has a motor gear, a main driven gear, and an auxiliary driven gear. The motor gear has a switching handle protruding out of the motor cover. The main driven gear and the auxiliary driven gear are oppositely disposed beside and engage with the motor gear. The main driven gear is disposed adjacent to the main no-fuse circuit breaker. A first transmission bar set is mounted between the main driven gear and the main no-fuse circuit breaker. The main driven gear has an eccentric lever protruding into and selectively driving the first transmission bar set. Thus, the first transmission bar set pushes a main switch handle of the main no-fuse circuit breaker. The auxiliary driven gear is disposed adjacent to the auxiliary no-fuse circuit breaker. A second transmission bar set is mounted between the auxiliary driven gear and the auxiliary no-fuse circuit breaker. The auxiliary driven gear has an eccentric lever protruding into and selectively driving the second transmission bar set. Thus, the second transmission bar set pushes an auxiliary switch handle of the auxiliary no-fuse circuit breaker.
When an operator turns the switching handle, circuits of the main no-fuse circuit breaker and the auxiliary no-fuse circuit breaker are “closed” to form electrical conductions or are “open” to interrupt the electrical conductions indirectly.
However, when the conventional transfer switch has problem in switching and causes the mains power source and the auxiliary power source to provide electrical power at the same time, a short circuit occurs and the factory facilities are damaged. Therefore, it is important to improve safety of using the conventional transfer switch.
To overcome the shortcomings, the present invention provides a transfer switch to mitigate or obviate the aforementioned problems.